46 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 25 



Since 1952, when quantitative sampling was begun in the San Pedro 

 area, to 1960, more than 4000 quantitative samples have been taken 

 which, with few exceptions, have yielded polychaetes most abundantly. 

 The processing of these samples is still continuing and is far from com- 

 plete. The polychaetes from the 13 offshore basins of southern California 

 have been named and described in a separate report (Hartman, 1960a, 

 pp. 78-164). Those from the 13 offshore canyons are being studied in 

 another separate report (in preparation). The species from intertidal, 

 shelf and slope depths are listed below, but it is expected that many 

 additional species will be added as the numerous samples are processed, 

 and their contents carefully examined. 



Family Polynoidae 



Genus Hesperonoe Chamberlin, 1919 



This genus has affinities with Hannotho'e Kinberg, from which it 

 differs in that notopodia and neuropodia each have setae of two kinds. 

 Two species are previously known, both from intertidal areas of the 

 northeastern Pacific Ocean and both commensal with non-related animals. 

 Another species is newly described. 



Key to Species of Hesperonoe 



1. Elytra smooth or nearly so, the surface tubercles, if present, 

 minute and limited to the region in front of the elytrophoral 

 scar 2 



1. Elytra with widely spaced tubercles over most of the upper sur- 

 face; marginal fringe present unless worn away; the larger 

 notosetae with pectinae reduced or obsolete; color in life deep 

 salmon ; commensal with ghost shrimp ( Callianassa calif ornien- 

 sis) H. complanata 1 



2. The thicker notopodial setae with extensive pectinae; elytral 

 margins smooth ; intertidal and commensal with Urechis caupo 

 (an echiuroid) H. adventor 



2. The thicker notopodial setae with few or no pectinae; elytral 

 margins slightly fimbriated ; commensal, probably with Listriolo- 

 bus pelodes (an echiuroid) H. laevis 



1 Hesperonoe hivanghaiensis Uschakov and Wu, 1959, p. 35, from the Yellow 

 Sea, is characterized by having subquadrate elytra adorned with a transverse 

 row of elongate papillae behind the elytral scar. 



